Use Modulo:
UPDATE [dbo].[SOMaster_TEMP] SET [BEND] = [Qty] % [STDB]
"Your code solved this line
UPDATE [dbo].[SOMaster_TEMP] SET [BEND] =[Qty] % [STDB]
I got result is 2. It is fine.
Then How i get 302. ( UPDATE [dbo].[SOMaster_TEMP] SET [BSTD] = [Qty] /[STDB])"
Ah - easy:
UPDATE [dbo].[SOMaster_TEMP] SET [BSTD] = CAST([Qty] / [STDB] AS INT)